A carefully conceived shadow campaign for electing Ronald Reagan to a second term is now in place with the blessings of the White House. Its aim is to keep Reagan troops in fighting fettle for 1984 while preserving the president's options to make a go or no-go decision late this summer.

Old Reagan war horse Lyn Nofziger has long advocated a less timid White House approach to the reelection campaign. Now, he is getting much of what he wanted, including involvement of some key White House officials in the effort.

On April 16, for instance, White House political adviser Ed Rollins, who succeeded Nofziger, attended a meeting of Reagan political operatives in New Hampshire.

Its avowed, though unannounced, purpose was the planning of next year's primary campaign. More such meetings are scheduled and not just in New Hampshire.

At the same time, Reagan has maintained a sliver of doubt about his intentions by refusing to authorize creation of a formal committee and by telling operatives who have visited the White House, "Don't do anything that would force me to disavow you." He says, as he always did during past campaigns, that he will make a decision when the time comes.

Such Reagan intimates as deputy chief of staff Michael K. Deaver appear to have no doubts, however. "He'll run," Deaver says.

Those who see Reagan regularly observe that he enjoys being president and that his wife Nancy seems comfortable as well.

Longtime Reaganites consider this comfortableness the key. As long as Reagan likes what he's doing, they suspect he'll keep doing it as long as the voters let him. His intimates believe this will be until 1989, when Reagan would leave office three weeks before his 78th birthday.

Lurking just over the New Hampshire horizon is the potentially important political issue of acid rain. Democratic front-runner Walter F. Mondale is using the issue against challenger John Glenn, and some Republicans believe that it could carry over into the fall campaign, particularly if the contest is between Mondale and Reagan.

One Republican who sees acid rain as a potent issue is New Hampshire Gov. John H. Sununu, who raised the subject with Reagan at a White House meeting last week. The president came back with quotations from the utility companies' party line, contending that the data on the acidity of New England lakes are inconclusive.

"With all due respect, Mr. President, I've made a good living off the utility companies, but they're not telling you the whole truth," responded Sununu, who holds a doctorate in mechanical engineering.

He went on to say that the administration should take the issue seriously and be prepared to deal with it in the 1984 campaign.

Reagan heeded the warning and asked Sununu to come up with data and recommendations that can be evaluated by William D. Ruckelshaus, the once and future administrator of the Environmental Protection Agency.

The word in the White House, incidentally, is that Reagan will make an environmental speech, the first of his administration, timed to coincide with the expected Senate confirmation of Ruckelshaus in mid-May.

Office of Management and Budget Director David A. Stockman learned during the most recent round of budget hearings that the way to make a pitch to the president is to use plenty of charts and graphics.

He put this lesson to good use recently during a Cabinet meeting when Agriculture Secretary John R. Block defended the marketing order system under which farmers maintain the price of fruit and nuts by limiting the amounts that can be sold and shipped. Echoing the view of his constituents, Block maintained that no fruit is wasted under this protective system.

As quickly as you can say waste, fraud and abuse, Stockman took out a sheaf of 8-by-10 photographs of rotting oranges and showed them to Reagan.

The pictures had the desired effect. Although the president hasn't announced that he will phase-out the marketing orders, White House officials say that Reagan has directed Block to move in that direction.

The president gave a clue to his intentions during a discussion with an adviser who pointed out that marketing orders are politically popular in California. "Don't tell me to make decisions for political reasons," Reagan responded.

Baffling Contention of the Week: "We think there is a parallel between federal involvement in education and the decline in profit over recent years," the president told USA Today last Tuesday. Neither the White House staff nor the interviewers can explain what that means.

The president hits the road again this week, speaking at a Cinco de Mayo event in San Antonio Thursday and to the National Rifle Association in Phoenix Friday before going to his Santa Barbara area ranch for the weekend.

He returns to the White House next Monday after a stopover in Ohio to address a commemorative ceremony for the late Rep. John M. Ashbrook, a conservative Republican stalwart for many years and an early advocate of a Reagan presidential candidacy. Reaganism of the Week: (In a speech Wednesday to the New York Daily News Crimefighters): "You realize there's nothing very average about the average American."